The present invention relates to a process for the manufacture of identity cards which are comprised of several layers.
Cards of this type are used as information carriers or data carriers for personal passports, passports, cheque cards, credit cards, identity cards and similar certificates of identity which must be rendered secure against complete forgeries by counterfeit cards and against falsifications by partial alteration of the personal data.
Previously proposed identity cards have been produced as fused laminates in which a card core carrying the identity information is protected by transparent films which are of a different nature than the card core. Thus, West German Offenlegungsschrift No. 2,308,876 describes an identity card consisting of a relatively thick carrier film and a thin transparent film, between which there is a special paper having internal features, such as watermarks, banknote printings or the like. These features serve as protection against forgeries and cause differences in the thickness of the paper. The three layers are plastified together in such a way that the internal features are manually, mechanically and/or visually detectable through the transparent film. Further markings which serve to identify the cardholder are provided at a suitable location of this known identity card. For example, a photograph in the form of a film transparency may be inserted during plastifying between the special paper and the carrier film and firmly bonded to the special paper. Furthermore, it is possible, at any desired point on the front or rear of the identity card, to laminate a strip of special paper, in accordance with known security technology, onto the outside of the plastic material as a field for later insertion of signatures or other handwritten entries.
West German Auslegeschrift No. 2,163,943 discloses a personal identity card which comprises a combination of a support layer, an electrically conductive layer, a barrier layer, a photoconductive layer with an organic photoconductor, an optional cover layer, a protective layer on the photoconductive layer or on the cover layer, a protective layer on the rear of the layer support and an optional cover layer on the last-mentioned protective layer. In this type of personal identity card, a number of different materials are assembled to give a laminate which, due to the lack of homogeneity of the individual layers, can be split apart so that it is possible to carry out forgeries.
This type of identity card is manufactured in such a way that the required data are printed on the inside of a transparent non-plastic polyvinyl chloride film by means of an offset printing machine. Then a printing ink layer having a high hiding power is printed on top, so that only the areas provided for the signature and the photograph of the cardholder are left uncovered. The photoconductive layer with an organic photoconductor is charged in a dark room to a voltage of -6 kV by means of a spray discharge. It is then inserted into a camera wherein an objective lens and a lighting arrangement are combined to photograph the cardholder. A further objective lens for photographing signs with the aid of the lighting arrangement may be included. After the image-forming exposure, a liquid developer is used to develop the electrostatic images which are then dried and bonded, without a fixing operation, to the photoconductive layer of the previously prepared surface-protecting layer, consisting of the polyvinyl chloride film, by means of a hot press. The rear is then provided with a transparent non-plastic polyvinyl chloride film which may carry any required data on its inside. The entire surface is printed with an additional white cover layer which covers an aluminum foil serving as a conductive layer. It is also possible to print the white cover layer directly upon the rear of the photoconductive layer with the organic photoconductor or to use a milky white sheet as a base for the light-sensitive element.
In the manufacture of this personal identity card, the recording carrier for the photograph of the cardholder will, at the same time, serve as an image carrier for the electrostatic charge image, i.e. an image transfer does not take place. As the card core, the recording carrier is laminated with polyvinyl chloride films which may contain any required data on their insides. It is obvious that this known manufacturing process precludes a production line of identity cards, in the manner of a conveyor-line production, for producing a high volume card output. Here, for each individual card, the respective cardholder must be photographed on the spot, which is a time-consuming procedure.